Heating-element-mounting construction



3 Sheets-Sheet l E. L. SMALLEY Filed May 22, 1928 ATTORNEY mf, L

July l, 1930.

HEATING ELEMENT MOUNTING CONSTRUCTION July 1, 1930. y E. L. SMALLEY1,768,865

HEATING ELEMENT MOUNTING CONSTRUCTION Filed May 22, 1928 3 Sheets-Shea?I2 IN V EN TOR.

A TTORNEY July l, 1930. E. L, sMALLEY HEATING ELEMENT MOUNTINGCONSTRUCTION Filed May 22 1928 3 Sheets-Sheet 5 u n n INVENTOR. Edwin)1522251 Q/ yBY A TTORNEY Patented July 1, 1930 UNITED- STATES PATENTOFFICE EDWIN L. SMALLEY, OF WHITEFIS BAY, WISCONSIN', ASSIGNOR TO HEVIDUTY ELECTRIC COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OFWISCONSIN' HEATING-ELEMENT-MOUNTING CONSTRUCTION Application led lay22',

an electric furnace structure.

Another object of my invention is to provide a construction oflightweight ceramic material for installation within a furnace chamberfor mounting heater elements therein in a manner whereby the speed ofheating from cold to operating temperature ma be increased.

nother object of my invention is to provide, a construction of heater.element support which will prevent foreign particles such as iron oxidefrom lodging back of the projecting flanges on the head of the heaterelement support in an electric furnace chamber construction.

Still another object of my invention is to rovide a preformed ceramicrefractory or installation in a cylindrical vertical electric furnace ina manner whereby the coils and reflecting plates are held inself-supporting positlon.

A further object of my invention is to provide a means of supporting aheating coil with its corrugated reflecting plate against a flat facedwall which permits of the use of heat insulating material in moldl edshapes and avoids the usual fire-brick lining.

A still further object of my invention is to provide a construction ofheater element mounting for maintaining a heater element adjacent theinterior walls of a furnace chamber in a manner in. which directradiation of heat from the turns of the heater element is not impeded.v

My invention will be more fully understood by referring to the followingspecification and the accompanying drawings in which; y

Figure 1 illustrates a fragmentary crosssectional view taken through anelectric fur- 1928. Serial No. 279,810.

nace embodying the principles of my invention; Fi 2 is an enlargedelevational view looking 1n the direction of line 2-2 in Figure l,showin the resistors and the mounting thereof wlthin an electric furnacein accordance with my invention; Fig. 3 is a cross-sectional viewthrough the furnace wall showing one method of mounting the heatingelements with respect thereto; Fig. 4 is a front View of the heatingelements illustrated in Fig. 3; Fig. 5 is a front view of one section ofthe refractory which serves to support the heating elements with respectto the furnace wall; Fig. 6 shows a crosssectional view through therefractory in line 6-6 of Fig. 5; Fig. 7 ilustrates a cross-sectionalview through the refractory on line 7-7 of Fig. 5; Fig. 8 illustratesthe arrangement of the heating elements within a circular furnacechamber where the heating elements are formed in accordance with theprinciples of my invention and Fig. 9 illustrates one of therefractories which serves to support the heating elements in thearrangement shown in Fig. 8.

The elimination of the fire-brick lining decreases, to a remarkableextent, the amount of time required in bringing the furnace from cold tooperating temperature. For example, a furnace constructed in accordancewith my invention has reached an operating temperature of 1600o F. inone hour and a quarter starting with the furnace cold, while with thesame kw. input per hour in the same size furnace having a firebricklining, it has required a period of three hours for the furnace to reachits operating temperature.

The elimination of the fire brick lining reduces the overall size of thefurnace, thereby using less floor space, and at the same time decreasesthe number of square feet of outside area of the furnace shell, andresults in a remarkably lower radiation loss from the furnace.

Referring to Fig. l of the drawings, reference character 1 designates aform of steel shell enclosing heat insulating material 2 and fire-brickarch 3, all forming furnace chamber 4. By means of special shapedrefractories 27 having iuted heads 28`and square headed bolts 32 andnuts 8, corrugated refiector plates 18 having coils 19 are retained inthe position shown against the side walls of the furnace chamber 4.AAnother shape of the special ceramic refractory 27, having a iluted head28 retains similar corrugated reflector plates and coils in the arch ofthe furnace. In certain other forms of refractory construction, I havesuccessfully used the bolted form of ceramic refractor mounted on a flatarch of a furnace, andr in the latter case I do away with the fire-clayarch shown in Fig. 1.

Fig. 2 is a typical illustration of a furnace wall 23 showing the methodof mounting a heating element consisting of a return bend coil 19 lodgedin corrugated reflecting and radiating plates 18. he refractory memberhas a body portion 26 and a base portion 27 with a spaced relationshipbetween projecting base 27 and ilutings 28, so that a corrugatedreflector plate 18 and heating coil 19 can be held in osition shown byoutline 33 in Fig. 6 as agalnst a ilat wall of a furnace; or a similarcorrugated refractory 18 and coil 19 can be supported in an angularposition, or in a horizontal or vertical position which makes theassembly suitable for a self-supporting assembly, as shown in Fig. 8.

It is sometimes desirable as against a flat surface wall to bolt these Ishaped refractories 26 to the outside furnace shell b means of bolts 32,as shown in Figs. 1 an 6, and shown in assemblyas tied 1n by nuts 8 in nFigs. 1, 2, 5 and 6 a square headed bolt 32 is shown lodged in hole 30,having square countersunk rece 31. Groove 35 at one end of refractoryoffers a reception means for lug 36 of an adjacent refractory, where amultiple number of such refractories are used. The combination of tongue36 in grooves 35 keeps successive numbers of refractories in ali nment.

n Fig.'3, 25'I is shown as a modified form of the special shaped ceramicrefractory, whereby the base portion 25 lodges in an undercut groove 24of a furnace wall 23, such furnace Wall being formed of any suitablematerial, such as fire-clay. These refractories 25 have ilutings 22projecting over return bends 20 of coils 19, and also overlap a portionof reflector plates 18, thereby retaining coil 19 in corrugatedreflector 18. The ceramic refractories 25 are slidably arranged in thegrooves of the furnace wall 23. These ilutin 22, of head portion 17, andflutings 28 o Figs. 5 and 6, provide spaces between the projectionsforming openings as 29 in Fig. 5. This affords direct radiation of theheat released from the return bends of coil 19 and causes a lowertemperature in the return bend than results with a solid of head. Whenthese ial shaped re acteries extend horizontal y, as in the side coil offurnace shown in Fig. 3, the openings 29'between thev fluti 22 preventthe accumulation of fine partic es, such .as iron oxide from accumulatling back of the free to flow throng Fi 5.

n Fig. 8 a transverse section of a vertical cylindrical or ot typefurnace is shown, having cylindrlcal steel shell 10, enclosing heatinsulating material 11, such as kieselguhr, forming furnace chamber 12.The inner surface of insulating wall' 11 may be c lindrical in form. Bymeans of the speclal shaped ceramic refractory of Fig. 7, shown as 42 inFig. 8, reflector plates 14 having coils 15 coiled thereon areself-supporting against the furnace walls. These refractories areself-bracing and are sustained by reason of 'their ownpositioning aroundthe interior of the furnace walls. This eliminates the necessit ofbolts, such as shown in Fi s. 1, 2, 5 an 6.

I have foun by actual practice and test that the tem rature of thereturn bends of coils lodged ack of fluted heads such as 28 is 50 to 75F. cooler than similar bends lodged back of flanges of solid type Tshaped supports, such as shown in the structure of my Letters Patent No.1,614,321, dated January 11, 1927 While I have described a referredembodiment of my invention, I esire it to be understood thatmodifications may be made by those skilled in the art within the scopeof the appended claims without departing from the rinciples of myinvention.

What claim as new and desire to secure 22, as the scale is openings 29as 'in by Letters Patent of the United States is as follows:

1. Means for mounting resistance elements within a furnace structurecomprising a plurality of refractory members extending from a furnace wal, said refractory member having a plurality of laterally extendingfluted portions, a heat reflecting member secured between the lutedportions of adjacent refractory members, said heat reflecting memberhavin a plurality of corrugations along the sur ace thereof, a resistorelement having a dplurality of turns, said turns being dispose in saidcorru ations in said heat reflecting member, and portions thereofextending beneath the fluted edges of said refractories, whereby saidturns are maintained in position with respect to said heat reflectingmember.

2. Means for mounting a resistor comprising a plurality of refractorymembers spaced one from the other, said refractory members each havingan overlapping flange portion, each flange portion being luted along theedge thereo a heat reflecting member loaving cated between saidoverlapping lian e portions, said heat reflecting member aving acorrugated surface, a resistor in the form of a wire member wound inparallel extendinfr turns in the corrugations of said heat re'flectinv.member with the turns thereof extexrdingtbeneath adjacent 'lutedportions of the flange portions of said refractories, the fluted edgeportions of each of said refractories being aligned with thecorrugations of said heat reflecting member and pro truding over thereturn'ends of the wire turns in said corrugations.

3. In an electric furnace structure a supporting member for a heaterelement comprising a refractory having a laterally extending corrugatedsurface for receiving the turns of a heating element, a web portionprotruding substantially perpendicular to said surface, said laterallextending surface having a plurality ofyserrations along the edgethereof, said serrations serving to en e portions of the heating elementfor malntaining the heating element in an operative osition. y

4. an electric furnace structure, a set of refractories extendingparallel one to the other and protruding perpendicular to the wall 0fthe furnace, said refractories having laterally extending surfacesthereon, a heat radiating surface constituted by a plate locatedintermediate said refractories, a multiplicity of corrugations in saidplate extending perpendicular to the axes of said refractories, and aheater element positioned between the corrugations in said heatradiating surface and the laterally extendin surfaces of saidrefractories, the lateral y extending surfaces of said refractoriesbeing serrated for maintaining said heater element 1n position betweensaid corrugations on said plate.

5. In an electric furnace structure, a set of refractories spaced onefrom another and protruding from a furnace wall, each of saidrefractories including a web portion and a laterally extending capportion, each cap portion being serrated along the edges with theserrated portions of each set of refractories directed toward eachother, a heat reflecting plate disposed between the web portions of saidrefractories, and a heating element carried by said heat reflectingplate and secured between the serrated portions of said refractories.

6. In an electric furnace structure, a set of parallel extendingrefractories protruding from the furnace wall, each of said refractoriesincluding a web portion and a top portion, the refractories of each setbeing interlocked end to end and havin a laterally extendin portionintegral wit said to i portion an serrated at the edges thereo a heatreflecting plate having a corrugated surface thereon, said plate beingdisposed be- In testimony whereof I aix m si naturea,70

EDWIN L. S L EY.

